Gliederung

Objective: Direct surgery for a cavernous malformation in the brainstem is indicated whenif becomes symptomatic or causes repeated hemorrhage. In this report, our surgical strategy, use of the intraoperative brainstem monitoring/mapping and surgical results will be reported.

Methods: Between April 2000 and December 2011, 21 lesions in 20 patients (6 men and 14 women, age ranged between 3 and 64 years, average age of 39.8 years, follow-up period of 3.4 years) were surgically treated. Lesions were located in the midbrain in 6 patients, in the pons in 13, in the medulla oblongata in 1, in the cerebellar peduncle in 1 (in one patient there were two lesions in the midbrain and pons). For the fourth-ventricular floor approach, brainstem mapping/monitoring was utilized especially for preserving facial nerve function.

Results: For the 21 lesions, 23 procedures were conducted: in one patient intentional two-stage surgery was performed, another patient needed second surgery for the residual lesion. In respect to the surgical approaches, 3 occipital transtentorial, 3 supracerebellar infratentorial, and one subtemporal approaches were used for the midbrain lesion; 7 trans-fourth ventricular floor, 2 anterior petrosal, 2 lateral suboccipital, and one supracerebellar infratentorial approach was used for the pontine lesions; the lateral suboccipital approach was used for the cerebellar peduncle lesion, the trans-fourth ventricular floor approach was used for the medulla oblongata lesion. For one patient with double lesions in the pons, total removal was achieved in a two-staged surgery with the trans-fourth ventricular floor approach. Total removal was achieved in 19 lesions, gross total removal in 2. In the postoperative phase, the Karnofsky performance state score increased in 18 patients and was unchanged in 1. One patient improved, but died of unrelated disease.

Conclusions: By selecting a suitable surgical approach with brainstem monitoring/mapping, the lesions were safely resected with minimal neurological deficits.